Whole-body parametric positron emission tomography (PET) imaging methods, such as Fludeoxyglucose (FDG) PET, are being considered. A tracer material, such as FDG is injected into the patient, and the uptake behavior is observed over time. Tumors and other regions having uptake behavior distinct from healthy tissue can be distinguished. Dynamic FDG PET imaging along with compartment modelling provides improved discrimination of lesions for scan duration of 90 minutes. However, such long scan durations may cause patient discomfort and motion and may not be a feasible option in a clinical setting. Karakatsanis, N. A. et. al., “Dynamic whole-body PET parametric imaging: I. Concept, acquisition protocol optimization and clinical application,” Phys. Med. Bio., vol. 58, p. 7391, 2013, describes a clinically feasible protocol in which whole-body dynamic PET data can be collected for about 30 minutes, starting 10 minutes post injection. Karakatsanis, N. A. et. Al. used Patlak graphical analysis to estimate the metabolic rate of glucose measures that were quantitatively similar to those obtained with 60 minutes scan duration. When Patlak analysis was performed on each voxel (voxel fitting) for short scan duration, the resulting slope parametric image, which represents the metabolic rate of glucose, is noisy.